EECE.3170 Microprocessor Systems Design I Instructor: Dr. Michael Geiger Spring 2016 Lecture 20: PIC instruction set

Microprocessors I: Lecture 20 Lecture outline Announcements/reminders HW 5 due 1:00 PM, 3/21 Coming up: HW 6 due 1:00 PM, 3/28—no late submissions Exam 2 in class Wednesday, 3/30 PICkits to be handed out after break Will have to work in groups (3 students preferred size) Today’s lecture: PIC instruction set intro 4/17/2019 Microprocessors I: Lecture 20

Microprocessors I: Lecture 20 4/17/2019 PIC16F1829 Instructions 49 instructions Each instruction is 14 bits Byte-oriented OPCODE f, F(W) Source f: name of a SFR or a RAM variable Destination F(W): F if the destination is to be the same as the source register W if the destination is to be the working register Bit-oriented OPCODE f, b Bit address b (0≤b≤7) Literal and control OPCODE k Literal value k 4/17/2019 Microprocessors I: Lecture 20 Chapter 9

PIC16F1829 Instructions (cont.) 4/17/2019 PIC16F1829 Instructions (cont.) MOVLP/MOVLB: move literal to PCL/BSR BRA: Relative branch FSR instructions used in indirect addressing 4/17/2019 Microprocessors I: Lecture 20 Chapter 9

Microprocessors I: Lecture 20 RAM variables Memory variable: symbolic name to refer to space in memory (GPRs) Usable space on 16F1829: offsets 0x20–0x7F Once declared, use symbolic name, not address Example PIC syntax (cblock/endc): cblock 0x20 ; cblock directive needs starting ; address var1 ; var1 = byte at 0x20 var2 ; var2 = byte at 0x21 var3 ; var3 = byte at 0x22 endc ; End of variable block 4/17/2019 Microprocessors I: Lecture 20

Microprocessors I: Lecture 20 4/17/2019 Microprocessors I: Lecture 20

Microprocessors I: Lecture 20 4/17/2019 Microprocessors I: Lecture 20

Microprocessors I: Lecture 20 4/17/2019 Clear/Move clrw ; Clear W register clrf f ; Clear f register movlw k ; move literal value k to W movwf f ; move W to f movf f, F(W) ; move f to F or W swapf f, F(W) ; swap nibbles of f, putting result in F or W STATUS bits: clrw, clrf, movf: Z movlw, movwf, swapf: none Examples: clrf TEMP1 ;Clear variable TEMP1 movlw 5 ;load 5 into W movwf TEMP1 ;move W into TEMP1 movwf TEMP1, F ;Incorrect Syntax movf TEMP1, W ;move TEMP1 into W ; movf TEMP1, TEMP2 ;Incorrect Syntax swapf TEMP1, F ;Swap 4-bit nibbles of TEMP1 swapf TEMP1, W ;Move TEMP1 to W, swap nibbles, leave TEMP1 unchanged 4/17/2019 Microprocessors I: Lecture 20 Chapter 9

Single Bit Manipulation 4/17/2019 Single Bit Manipulation bcf f,b Operation: Clear bit b of register f, where b=0 to 7 bsf f,b Operation: Set bit b of register f, where b=0 to 7 STATUS bits: none Examples: bcf PORTB, 0 ;Clear bit 0 off PORTB bsf STATUS, C ;Set the Carry bit 4/17/2019 Microprocessors I: Lecture 20 Chapter 9

Microprocessors I: Lecture 20 Example Show the values of all changed registers after the following sequence cblock 0x30 x y endc clrw movwf x movlw 0xFE movwf y swapf y, F bcf y, 3 bsf x, 3 movf y, W 4/17/2019 Microprocessors I: Lecture 20

Microprocessors I: Lecture 20 Example solution clrw  W = 0x00 movwf x  x = W = 0x00 movlw 0xFE  W = 0xFE movwf y  y = W = 0xFE swapf y, F  Swap nibbles of y  y = 0xEF bcf y, 3  Clear bit 3 of y = 1110 11112  y = 1110 01112 = 0xE7 bsf x, 3  Set bit 3 of x  x = 0000 10002 = 0x08 movf y, W  W = y = 0xE7 4/17/2019 Microprocessors I: Lecture 20

Increment/Decrement/ Complement 4/17/2019 Increment/Decrement/ Complement incf f, F(W) ; increment f, putting result in F or W decf f, F(W) ;decrement f, putting result in F or W comf f, F(W) ;complement f, putting result in F or W STATUS bits: Z Examples: incf TEMP1, F ;Increment TEMP1 incf TEMP1, W ;W <- TEMP1+1; TEMP1 unchanged decf TEMP1, F ;Decrement TEMP1 comf TEMP1, F ;Change 0s and 1s to 1s and 0s 4/17/2019 Microprocessors I: Lecture 20 Chapter 9

Addition/Subtraction 4/17/2019 Addition/Subtraction addlw k ;add literal value k into W addwf f, F(W) ;add w and f, putting result in F or W sublw k ;subtract W from literal value k, putting ;result in W subwf f, F(W) ;subtract W from f, putting result in F or W STATUS bits: C, DC, Z Examples: addlw 5 ; W <= 5+W addwf TEMP1, F ; TEMP1 <- TEMP1+W sublw 5 ; W <= 5-W (not W <= W-5 ) subwf TEMP1, F ; TEMP1 <= TEMP1 - W 4/17/2019 Microprocessors I: Lecture 20 Chapter 9

Microprocessors I: Lecture 20 Final notes Next time: Continue with PIC instructions (M 3/21) Enjoy your break! Reminders: HW 5 due 1:00 PM, 3/21 Coming up: HW 6 due 1:00 PM, 3/28—no late submissions Exam 2 in class Wednesday, 3/30 PICkits to be handed out after break Will have to work in groups (3 students preferred size) 4/17/2019 Microprocessors I: Lecture 20